store SkAlphaType inside SkBitmap, on road to support unpremul

src/lazy/SkLazyPixelRef.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Sk64.h"
 #include "SkLazyPixelRef.h"
 #include "SkColorTable.h"
@@ skipping 132 matching lines @@
 
 SkData* SkLazyPixelRef::onRefEncodedData() {
     fData->ref();
     return fData;
 }
 
 #include "SkImagePriv.h"
 
 static bool init_from_info(SkBitmap* bm, const SkImage::Info& info,
                            size_t rowBytes) {
-    bool isOpaque;
-    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
+    SkBitmap::Config config = SkImageInfoToBitmapConfig(info);
     if (SkBitmap::kNo_Config == config) {
         return false;
     }
 
-    bm->setConfig(config, info.fWidth, info.fHeight, rowBytes);
-    bm->setIsOpaque(isOpaque);
-    return bm->allocPixels();
+    return bm->setConfig(config, info.fWidth, info.fHeight, rowBytes, info.fAlphaType)
+           &&
+           bm->allocPixels();
 }
 
 bool SkLazyPixelRef::onImplementsDecodeInto() {
     return true;
 }
 
 bool SkLazyPixelRef::onDecodeInto(int pow2, SkBitmap* bitmap) {
     SkASSERT(fData != NULL && fData->size() > 0);
     if (fErrorInDecoding) {
         return false;
@@ skipping 17 matching lines @@
 
     target.fAddr = tmp.getPixels();
     fErrorInDecoding = !fDecodeProc(fData->data(), fData->size(), &info, &target);
     if (fErrorInDecoding) {
         return false;
     }
 
     *bitmap = tmp;
     return true;
 }